The GUESA science acronym gives students a fixed order for solving math based science problems: Givens, Unknown, Equation, Substitute, Answer. Science teachers, especially in physical science, physics and chemistry, use it so that every problem gets set up the same way before any arithmetic starts.
The method turns a paragraph of words into a short, orderly worksheet. It also leaves a clear trail, so a teacher can see exactly where a mistake happened and give partial credit for the steps that were right.
Quick facts
Stands for
Givens, Unknown, Equation, Substitute, AnswerType
Mnemonic acronymUsed in
Physical science, physics, chemistry, some math classesBest for
Word problems that use a formulaAlso written
G.U.E.S.A., or with Given in place of GivensKey habit
Keep units with every number
What the GUESA science acronym stands for
| Letter | Step | What to write |
|---|---|---|
| G | Givens | Every number the problem tells you, with its unit and symbol |
| U | Unknown | The quantity you need to find, with a question mark |
| E | Equation | The formula that connects the givens to the unknown |
| S | Substitute | The formula again, with numbers and units plugged in |
| A | Answer | The result, rounded sensibly, with the correct unit |
Some teachers say "Given" instead of "Givens." The letters and the steps stay the same.
A worked example: speed
Problem: A cyclist rides 150 meters in 30 seconds. What is her average speed?
G: d = 150 m, t = 30 s
U: v = ?
E: v = d / t
S: v = 150 m / 30 s
A: v = 5 m/s
Notice that the unit in the answer, meters per second, comes straight out of the substitute line. Keeping units with the numbers is a quick check that you used the right formula.
A second example: force
Problem: A cart with a mass of 12 kg speeds up at 3 m/s². How much force is pushing it?
G: m = 12 kg, a = 3 m/s²
U: F = ?
E: F = m × a
S: F = 12 kg × 3 m/s²
A: F = 36 N
One newton (N) is one kilogram meter per second squared, which is why the units in the substitute step turn into newtons in the answer.
Tips that make GUESA work
- Hunt for hidden givens. "Starts from rest" means the starting speed is zero. "Dropped" often means the acceleration is gravity.
- Convert units first. If one time is in minutes and the formula expects seconds, fix it in the givens line.
- Rearrange before you plug in. If the unknown is not alone in the formula, solve for it with letters in the E step.
- Box the answer. Many teachers ask for this so the final value stands out.
- Ask if it makes sense. A walking speed of 900 m/s means something went wrong.
Why teachers like the method
Students often freeze on word problems because the numbers are buried in sentences. Writing the givens and unknown first separates reading from math. The equation step forces a choice of formula before any calculator comes out, and the substitute line makes errors easy to find. It also matches how lab reports and tests are graded, so the habit pays off beyond homework.
GUESA fits well beside other classroom memory aids such as PEMDAS for order of operations. The steps also mirror the logic of STEM problem solving generally: define, plan, calculate, check.
GUESA and other problem solving acronyms
Some textbooks swap in slightly different labels, such as "Required" for the unknown or "Solution" for the substitute step. Every version shares one core idea: write what you know, what you need and how they connect before you calculate. In geometry class, a different memory tool, CPCTC, helps with proofs. You will find more study shortcuts in the memory acronyms collection.
Questions people ask
What does GUESA stand for in science?
GUESA stands for Givens, Unknown, Equation, Substitute, Answer. It lists the steps for solving a science word problem that uses a formula.
Is GUESA only for physics?
No. It is common in physics and physical science, but it works for chemistry, earth science and any problem that plugs numbers into a formula.
What goes in the givens step?
Write each number from the problem with its symbol and unit, such as m = 12 kg. Include hidden givens, like a starting speed of zero.
Do I need to write units in every step?
Most teachers expect units in the givens, the substitute line and the answer. Units help you catch mistakes and are often part of the grade.
How do you say GUESA?
There is no single official way. Many students spell out G, U, E, S, A, while others blend it into one word, and teachers accept either.